In recent years, alignment accuracy of 0.1 μm or higher is required in integrated semiconductor circuits, in order to achieve a line width of between 0.25 and 0.3 μm. To achieve such high-accuracy positioning, a moving table device is utilized in semiconductor manufacturing systems. High-accuracy positioning is also required in precision measurement systems and precision assembly systems, and a moving table device is utilized in these systems as well.
One type of known conventional moving table devices is the so-called X-Y-θ table. In the general configuration of the X-Y-θ table, three movable mechanisms, one each of which moves in the X Y, and θ axial directions respectively, are stacked on a base and support a table that is placed on top.
However, the configuration in which movable mechanisms in the X, Y, and θ axial directions are stacked has various problems such as: the large number of components required; instability resulting from the tall height from the base to the table; the decreased accuracy in the upper mechanism(s) successively caused by the effects of the moving mechanism(s) below; difficulty in ensuring accuracy when combining the three moving mechanisms of the X, Y, and θ axial directions; and the damage and failure caused by the movements of the cables for the mechanisms of the X, Y, and θ directions.
To solve such problems, Japanese Patent No. 2700050, for example, suggests an apparatus which has a supporting unit comprised of a pair of linear-motion guiding bearings, each of which consists of a guiding part and a movable part, and which both of movable parts are rotatably linked to each other, a base linked to one of the guiding parts of the linear-motion guiding bearings; and a table linked to the other guiding part.
However, in this conventional supporting unit, the movable parts are linked to each other, and the guiding parts only allow the movable parts to move in the guided direction. As a result, this configuration only allows the movable parts to rotate in the forward or reverse direction and to move along the individual guiding parts, while the guiding parts are fixed. Consequently, it is not possible to correctly install the supporting unit unless the base and the table are held in an almost perfectly parallel relationship to each other (specifically, at an accuracy of 0.05 μm or higher), complicating the installation of the supporting unit. Worse yet, forcibly installing the supporting unit can deform the bearing, preventing smooth operations.
Another type of apparatus that has the same kinds of problems is the linear-motion guiding device. In one type of known linear-motion guiding device, a slider is linearly moved along a guide block. To drive the slider, a drive mechanism that uses a ball screw and a ball nut is provided and is linked to the slider via a supporting unit. Such a linear-motion guiding device encounters the same problems as those described above during the installation of the supporting unit.
The present invention has been conceived in view of the aforementioned situation, and an objective is to provide a supporting unit that can be easily installed without the risk of bearing deformation, as well as a moving table device and a linear-motion guiding device that use the supporting unit